Problem: Express this number in scientific notation. $0.000\;430\;9$
Answer: Count the zeroes to the right of the decimal point before the leading $\leadingColor{4}$ : there are $3$ zeroes If you count the leading digit $\leadingColor{4}$ and those zeroes , there are $\exponentColor{4}$ digits to the right of the decimal point. So: $0.000\;430\;9 = \leadingColor{4}.309 \times 10^{\exponentColor{-4}}$